问题 选择题

某静电场的电场线分布如图所示,P、Q为电场中的两点.则下列说法正确的是(  )

A.P点电势一定高于Q点电势

B.P点场强一定小于Q点场强

C.负电荷在P点的电势能大于在Q点的电势能

D.若将一试探电荷+q由P点释放,它将沿电场线运动到Q点

答案

解;A、根据沿电场线方向电势降低可知:P点电势一定高于Q点电势,故A正确.

B、电场线密的地方电场的强度大,所以P点场强一定大于Q点场强,故B错误.

C、P点电势一定高于Q点电势,即φp>φq

电势能Ep=qφ,由于是负电荷,所以q<0,所以负电荷在P点的电势能小于在Q点的电势能.故C错误.

D、将一试探电荷+q由P点释放,它受切线方向的电场力,所以不可能沿电场线运动到Q点,故D错误.

故选A.

完形填空

People who are confident really seem to be naturally outstanding and just seem to do everything with more style than others.    小题1:  It is a habit that everyone can develop in life. Try these simple tips to drill and build up your confidence:

1. Admit your shortcomings calmly.

Do not try to flee from them or cover them. Face them bravely.  小题2:   Fight against them every day until the day when you could break away and conquer them.

2. Dress for self-confidence.

 小题3:  And therefore pay attention to your dress, display your unique physical advantages and exhibit your best image. In addition, on formal occasions such as a business conference or a wedding ceremony, elegant dressing contributes to building your confidence.

3.  小题4:  

You should break your routine that deals with the work passively(被动地). Concentrate your efforts immediately on overcoming it, because it will make your restless mind at ease and build your self-confidence.

4. Be positive.

Feel pity neither on yourself nor on others. If you are used to hating and accusing yourself, others would tend to do that and believe it. Instead, you should speak positively about yourself, your progress, and your bright future.    小题5:

A.Your appearance could put you into embarrassment or increase your confidence.

B.Then talk about them to a reliable mate, a friend or a family member.

C.Actually, true self-confidence is neither born nor acquired overnight.

D.Build your confident vocabulary.E. By doing so, you would encourage your growth in a positive direction.

F. Don’t put off what you eventually have to do.

G. Don’t judge a person by appearance.

判断题